Apparatus for taking samples of fibrous materials



K. L. HERTEL Oct. 9, 1962 APPARATUS FOR TAKING SAMPLES OF FIBROUS MATERIALS 5 Sheets-Sheet 1 Filed Jan. 13, 1960 5 Sheets-Sheet 2 V Qk.

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Oct. 9, 1962 K. L. HERTEL APPARATUS FOR TAKING SAMPLES OF FIBROUS MATERIALS Filed Jan. 15, 1960 K. L. HERTEL Oct. 9, 1962 APPARATUS FOR TAKING SAMPLES 0F FIBROUS MATERIALS Filed Jan. 13, 1960 5 Sheets-Sheet 3 INVENTOR. fill F1115 L. Henna Och 1962 K. L. HERTEL 3,057,019

APPARATUS FOR TAKING SAMPLES OF FIBROUS MATERIALS 5 Sheets-Sheet 4 Filed Jan. 13, 1960 INVENTOR ATTORNEY O 6 K. L. HERTEL 3,057,019

APPARATUS FOR TAKING SAMPLES OF FIBROUS MATERIALS Filed Jan. 15, 1960 5 Sheets-Sheet 5 INVENTOR. lira/1 1ml fifwarzz United States Patent Ofifice 3,057,019 Patented Oct. 9, 1962 APPARATUS FOR TAKING SAMPLES F FIBROUS MATERIALS Kenneth L. Hertel, Knoxville, Tenn., assignor to University of Tennessee Research Corporation, Knoxville,

Tenn, a. corporation of Tennessee Fiied Ian. 13, 1960, Ser. No. 2,170 19 (Zlaims. (Cl. 19-65) This invention relates to improvements in apparatus for measuring the fiber length of ginned cotton, apparatus for this general purpose being shown in my two prior Patents No. 2,299,983, issued October 27, 1942, and No. 2,404,708, issued July 23, 1946.

The first of the above patents relates to an optical method and instrument for measuring the fiber length of cotton contained in a pre-arranged sample, the fibers of which have been combed out into substantially parallel relation. The second patent relates to apparatus for preparing such samples.

The apparatus disclosed in said second Patent No. 2,404,708 comprises a pair of freely movable combs by means of which random bits or tufts of cotton, picked up with th fingers, and manually placed upon the teeth of one of the combs, can be combed out by manipulating the other comb until the fibers are straightened out into substantially parallel relation.

The general object of the present invention is to devise apparatus by means of which the necessity for picking up bits of cotton and placing them on a comb by hand is avoided, and in which a comb, moving in a fixed path, gathers a representative sample from a stationary mass of cotton. Such apparatus can not only provide samples much mor easily and rapidly, but also can produce more uniform samples.

A specific object is to provide improved means for supporting the mass of cotton in position to be efiectively contacted by the comb, and improved means for mounting the comb for movement in a fixed path past such mass.

Another specific object of the invention is to devise an improved comb or sample holder having means by which, after the sample has been collected on the teeth, it may be clamped or locked in position on th teeth while the fibers are being straightened out into parallel relation.

A still further object is to provide improved means for combing or straightening out the ends of the fibers locked in the sample holder.

This means for combing or straightening out the fibers comprises a piece of card clothing, and yet another object of the invention is to devise effective means for cleaning oflf the excess cotton that becomes embedded in this card clothing.

With the above and other objects in view, and to improve generally on the details of such apparatus, the invention consists in the construction and arrangement of parts hereinafter described and claimed, and illustrated in the accompanying drawings, forming part of this specification, and in which:

FIG. 1 is a side elevation of the complete apparatus;

FIG. 2 is a front end elevation of the same;

FIG. 3 is a transverse section through the apparatus shown in FIGS. 1 and 2;

FIG. 3a is an enlarged detail showing the preferred shape of the card teeth;

FIG. 4 is a fragmentary elevation on an enlarged scale of a portion of the upper front edge of the machine showing the sample holder in two different positions;

FIG. 5 is a plan view of the sample holder as it appears when in open condition, parts being broken away and parts being shown in section;

FIG. 6 is a fragmentary view similar to FIG. 5 but showing the sample holder in closed position;

FIG. 7 is a transverse section on the line 7--7 of FIG. 5;

FIG. 8 is a fragmentary view on an enlarged scale showing rnOre clearly the sample holder and associated parts illustrated in FIG. 3;

FIG. 9 is a fragmentary end elevation of the sample holder, showing partly in section a device for insuring that the sample holder is in open position as it begins its movement;

FIG. 10 is a fragmentary side elevation Viewed from the line 1010 of FIG. 9 looking in the direction of the arrows;

FIGS. 11 and 12 are transverse sections on an enlarged scale through the sample holder, showing the parts thereof in different positions;

FIG, 13 is a fragmentary plan view of the threaded core of the sample holder;

FIG. 14 is a transverse section on the line 14-14 of FIG. 13;

FIG. 15 is a fragmentary plan view of the body of the sample holder;

FIG. 16 is a transverse section on the line 16-16 of FIG. 15;

FIG. 17 is a fragmentary transverse section on an enlarged scale showing the dolfing device illustrated at the bottom of FIG. 3;

FIG. 18 is a fragmentary elevation generally similar to FIG. 4, but with certain parts omitted, showing a modified construction of arm for co-operation with the sample holder; and

FIG. 19 is a side elevation showing this arm and a fragment of the cylinder on which it is mounted.

Referring to the drawings in detail and more particularly first to FIGS. 1, 2 and 3 thereof, my improved apparatus comprises a U-shaped bracket 1 having upper and lower jaws 2 and 3. This is adapted to be applied to the edge of a table x or the like by means of one or more clamping screws 4 working through the lower jaw 3 and preferably bearing against a socket member 5 which may have a layer of felt or other soft material 6 interposed between it and the table.

Th bracket 1 has a horizontally projecting portion 7 in which is mounted one end of a shaft 8 held in position by a set screw 9. It will be noted that this shaft preferably extends at an angle of about 45.

Fixedly secured to the upper end of the shaft 8 is the bottom 10 of a hollow cylinder 11. This cylinder has upper and lower rims 12 and 13. The wall of the cylinder is composed in part of a curved plate 14 having openings 15 extending therethrough. By reference to FIGS. 1 and 2 it will be seen that these openings are relatively large compared with the distance between them and that the openings are circumferentially staggered so that every arcuate line drawn on the plate will pass through a number of these openings.

The part of the cylindrical wall not occupied by the plate 14 is formed of a solid plate 17 on which is supported a strip of card clothing 16. The points of the card teeth 16a are inclined in a clockwise direction as viewed in FIGS. 2 and 3. Preferably the end 16b of each too-th lies on the same radial line as the point 16c where the tooth enters the cloth backing, as shown in FIG. 3a. This form of tooth is less likely to be bent out of shape by the cotton.

At the lower side of the cylinder between the perforated plate 14 and the card clothing 16 is an open reentrant channel 18, the purpose of which will hereinafter appear.

Mounted to rotate freely on the shaft 8 between the bracket 7 and the cylinder bottom It) is a carriage 19 (see FIGS. land 3). A portion of this carriage extends downwardly and forwardly as shown at 2! and is formed with a cylindrical portion at the bottom as illustrated in FIG. 3.

Fixedly mounted on this carriage is a channel member 21 and in this channel member is removably received and supported the sample holder 22.

As best shown in FIGS. 11 and 12, this sample holder comprises an elongated body 22 rectangular in cross section having a cylindrical bore extending longitudinally thereof, and a core rotatable therein. The bore of the body 22 is threaded as at 220 like an ordinary nut while the core 24 is similarly threaded as at 24s to work inside of the threaded nut.

The body or nut 22 has an open slot extending longitudinally along one side, this slot having a high edge 22a and a low edge 22b. As clearly shown in the drawing, the threaded core 24 projects up through this slot.

Secured to the high edge 22a of the body 22 is a comb device comprising a series of horizontally extending teeth 27 projecting inwardly partially across the above mentioned slot. I find that the best results are obtained by making these teeth 27 of individually fabricated needle points, these needle points being disposed in spaced parallel relation as shown in FIG. 5 and secured to the edge 22a of the body as by means of solder 22d. The spacing of these needle points is not definitely critical but may vary from about 12 to per inch.

Along a zone extending longitudinally of the core 24 the threads 240 are cut away at one side to produce a flat channel-shaped recess 24a. When the core 24 is turned so that this channel underlies the projecting needles or teeth 27 as shown in FIG. 11, the sample holder may be said to be in open position. In other words, the clearance between the needle points and the bottom of the channel permit fibers to enter between the needle points and the bottom of the channel.

Referring again to FIGS. 11 and 12, it will be seen that when the core 24 is rotated slightly in a counterclockwise direction from the position shown in FIG. 11, the bottoms of the threads 240 are brought under and in substantial contact with the needle points as illustrated in FIG. 12', thus changing the sample holder to closed position.

n An angular shaped handle member 23 is rigidly secured to one end of the body 22 and the core 24 is rotated as described by means of a crank arm 25 projecting from a hub 26 secured to the end of the core. When this crank arm extends substantially horizontally as shown in FIGS. 5, 9 and 10, the sample holder is in open position as shown in FIG. 11. Whereas if the crank arm is swung in a counterclockwise direction into some such position as shown in full lines in FIG. 4, the sample holder is placed in closed position as illustrated in FIG. 12.

It will be understood that in operation, the carriage 19 on which the sample holder is mounted is swung in a counterclockwise direction around the shaft 8. It will further be understood that by reason of the weight of the carriage and of the various instrumentalities hereinafter described mounted thereon, the carriage is normally maintained by gravity in the position shown in FIGS. 1, 2 and 3, with the sample holder adjacent the re-entrant channel 18 formed in the cylinder. It will now be apparent that the purpose of this re-entrant channel is to afford ready access to the sample holder so that it may be easily removed and replaced.

In order to assure that the sample holder starts on 1ts travel around the cylinder in open position, a special bracket 28 is secured to the rim 12 of the cylinder adjacent the channel 18 and projects downwardly into the path of movement of the crank arm 25. This bracket has a notch on its underside having flaring cam surfaces 29 and 30 on either side. A pin 31 is set rigidly into the outer edge of the crank arm 25, as clearly shown in FIGS. 2, 5 and 6, for the purpose hereinafter explained, and by reference to FIG. '10 it will be seen that the notch in the bracket 28 is of sufiicient depth to permit this pin to pass through it.

Thus it will be seen that as the carriage and sample holder begin to swing toward the right, from the position shown in FIGS. 3 and 8, the crank arm 25 Will pass between the cam surfaces 29 and 3t and, whatever the initial position of this might have been, it will be automatically swung to the position shown in FIG. 9, thus placing the sample holder in open condition.

In order to resiliently hold the crank arm 25 in closed position, I provide on the inner edge of the arm a spring pressed ball 32, a spring 33 being confined by a set screw 34, as shown in FIG. 5. This ball 32 projecting from the edge of the crank arm 25 is adapted to engage the fixed handle 23 to hold the arm in closed position.

As shown in FIGS. 2 and 4, an arm 35 is pivotally mounted at one end on a shaft 36 carried by a projection 12a on the rim 12, a spring 37 being provided for normally maintaining this arm in the position shown in FIG. 2 and in dotted lines at the extreme right of FIG. 4. This arm 35 has a beveled outer end 38 from which projects a pin 39, this pin being located near the center of the arm so that a shoulder 40 is provided between the pin and the edge of the arm. As the. sample holder is moved in a counterclockwise direction around the cylinder, the pin 31 carried by the crank arm 25 engages this shoulder 40, as shown in dotted lines in FIG. 4, and by reason of the fact that it also engages the pin 39' it carries the arm 35 with it. As the arm 35 swings on its pivot, from the position shown in dotted lines to the position shown in full lines in FIG. 4, the crank arm 25 will be swung in a counterclockwise direction. As the sample holder moves slightly further to the left, as viewed in FIG. 4, the pin 39 will pass under the pin 31 and the arm 35 will be snapped back to normal position by the spring 37. The crank arm 25 will, however, remain in the position to which it has been turned, due to friction. In this position it is in closed condition.

In operation, the operator grasps a mass of fibrous material such as raw cotton and presses it against the inside of the perforated plate 14, as shown at A in FIG. 3. The pressure causes portions or tufts of the cotton to protrude through the openings 15, as shown at B. Then when the carriage is swung around the cylinder, as indicated by the arrow, the sample holder being in open position, the teeth 27 will gather or collect fibers from the protruding portions B, as shown at C in FIG. 11. The purpose of using a perforated plate is to present to the teeth of the comb approximately equal tufts of cotton in order that the sample collected may be as uniform as possible. As the sample holder completes its travel over the plate 14 and arrives at the position shown in full lines in FIG. 4, it will have been moved to closed position by the arm 35, as

above described, in which closed position the fibers are locked against the teeth by engagement of the threads 240, as shown in FIG. 12. At the same time, the fibers collected by the teeth are clamped between the edge 24d of the core threads, and the edge 22e of the body threads 22c. (See FIGS. 12 and 16.)

From the position shown in FIG. 4, the sample holder, carrying the fibers which it has collected, passes on around the cylinder and over the card clothing 16, which card clothing tends to straighten out the fibers so that they lie in substantially parallel relation. The card clothing also serves to remove from the holder any unclamped fibers. The fibers, after having been combed out by the card clothing, will present somewhat the appearance shown at C in FIG. 5. The sample holder, carrying the combed out fibers, can then be removed from the channel 21 for purposes of test and measurement.

From an inspection of FIGS. 11 and 12, it will be seen that the core threads 240 are slightly flattened or ground off, as shown at 24b. This flattened portion, when the holder is in closed position as in FIG. 12, is substantially horizontal, and is for the purpose of permitting the sample holder to run as close as possible to the card clothing.

In order to clean the excess fibers from the card clothing 16, I provide a doffer roll 41 rotatably mounted in a bracket 42, 42a pivoted at 43 on the carriage 19. This doffer roll has an operating knob 44 at its upper end so that it may be turned by hand. Incidentally, by grasping this knob, the operator can readily swing the carriage around the cylinder, as described. Normally, the dofier roll 41 is spaced a substantial distance from the cylinder, as shown in FIG. 3, but when it is desired to use it to clean the excess fibers from the card clothing, it is necessary to swing it inwardly on its pivot 43 into close proximity to the surface of the cylinder. The bracket 42, 42a is normally locked in the position shown in FIG. 3 by a bolt 45 urged by the spring 46 into engagement with a latch 48 (see FIG. 1), a knob 47 being provided at the upper end of the bolt 45 by means of which the bolt may be moved out of engagement with the latch so as to permit the bracket 42, 42a and dofi'er roll to swing in toward the cylinder.

In order to clean off the cotton fibers which may collect on the doffer roll, I provide the cleaning device shown at the bottom of FIG. 3 and in FIG. 17. This consists of a dofiing comb 56 carried by a bar 52, which bar also carries at each end a guide rod 53. Slidably mounted on the comb 56 and guide rods 53 is the downwardly bent portion 55 of a plate 54. This plate 54 is rigidly connected at 57 with one end of a link 58, the other end of which is pivoted at 59 to the carriage 19.

The bar 52 is carried by a curved plate 50 which fits around the similarly curved end of the portion 20 of the carriage and is also pivotally mounted on the pivot rod 43. An operating knob 51 is secured to this plate.

Thus it will be seen when the plate is swung in a clockwise direction, by means of this knob, from the full line position to the dotted line position shown in FIG. 3, the portion 55 of the plate 54 will be pushed outwardly along the guide rods 53 and comb 56, so as to strip the fibers from the comb. When in full line position, of course the comb 56 is in contact with the doffer roll, and when this roll is turned by means of the knob 44, the fibers collected thereon are cleaned off by the comb.

In order to balance the carriage 19 and cause it to swing easily, I preferably provide a counter weight 60 at the end of the carriage opposite the parts just described.

In FIGS. 18 and 19, I have illustrated a modified form of the means shown in FIG. 4 for setting the sample holder in locked position. Instead of the relatively heavy, spring-actuated arm 35 in FIG. 4, I employ, in FIGS. 18 and 19, a light arm or finger 61, made of a steel rod, and having its end bent as at 62, to engage the pin 31 of the crank arm 25. This arm is not spring-actuated but is freely pivoted in a bushing or bearing 63, and is returned by gravity to rest against the stop screw 64.

To hold the arm in position and protect it, I provide an overlying guard plate or shield 65. This is supported by the screw 64 and another screw 66, set into the rim 12. This is spaced from the rim, as shown in FIG. 19. Pivoted on the screw 66, beneath the cover 65, is an adjustable stop member 67, against which the arm impinges to limit its swinging movement.

The arm 65, formed simply of a piece of metal rod, may be considered an expendable part which may easily be replaced if accidentally bent or broken.

What I claim is:

1. Apparatus for producing samples of fibrous material from a loose mass, comprising a stationary plate having a plurality of openings therein, said openings being relatively large as compared with the distance between them, whereby when a mass of fibrous material is pressed against one side of said plate, portions of said material will project slightly through said openings and protrude from the other side of said plate, and a comb mounted to travel in a fixed path parallel with said plate over such protruding portions in contact therewith so as to gather fibers therefrom.

2. Apparatus according to claim 1, in which the plate is in the form of a section of a hollow cylinder, and the comb is mounted to swing in an arcuate path about the axis of said cylinder and around the outer surface thereof.

3. Apparatus for producing samples of fibrous material from a loose mass, comprising a stationary hollow cylinder, means for supporting said cylinder with its axis inclined at an angle to the horizontal, said cylinder composed partly of a plate having a plurality of openings therein, a carriage mounted adjacent said cylinder to rotate about the inclined axis thereof, and a comb device removably carried at one side of said carriage parallel with said axis in position to travel over the outer surface of said plate as the carriage is swung around said axis, the side of said carriage carrying said comb device being heavier than the opposite side, so that the carriage is maintained by gravity in a position in which said comb device lies at the lowermost side of the cylinder.

4. Apparatus for producing samples of fibrous material from a loose mass, comprising a stationary hollow cylinder, means for supporting said cylinder with its axis inclined at an angle to the horizontal, said cylinder composed partly of a plate having a plurality of openings therein, a carriage mounted adjacent said cylinder to rotate about the inclined axis thereof, and a comb device removably carried at one side of said carriage parallel with said axis in position to travel over the outer surface of said plate as the carriage is swung around said axis, the side of said carriage carrying said comb device being heavier than the opposite side, so that the carriage is maintained by gravity in a position in which said comb device lies at the lowermost side of the cylinder, said cylinder being formed at its lowermost side with a reentrant channel to permit ready access to said comb device for removal thereof.

5. Apparatus for collecting test samples from a loose mass of fibrous material comprising a stationary hollow cylinder the wall of which is composed partly of a plate having a plurality of openings therein, said openings be ing relatively large as compared with their distance apart, whereby, when a mass of loose, fibrous material is pressed against the inside of said plate, portions of said material will project slightly through said openings and protrude from the outside of said plate, a comb device extending parallel with the axis of said cylinder and mounted to swing about said axis at such a radial distance therefrom that said comb device sweeps closely around the outer surface of said cylinder, said comb device, in its initial movement, passing over said plate and gathering a sample of fibrous material from the portions protruding through the openings therein, and means carried by said cylinder, and over which said comb device passes by a further movement in the same direction for straightening out the fibers of said sample into substantially parallel relation.

6. Apparatus for collecting test samples of fibrous material from a loose mass comprising a stationary hollow cylinder composed partly of a plate having a plurality of openings therein and partly of a sheet of card clothing, said openings being relatively large as compared with their distanceapart, whereby, when a mass of loose, fibrous material is pressed against the inside of said plate, portions of said material will project slightly through said openings and protrude from the outside of said plate, and a comb device extending parallel with the axis of said cylinder and mounted to swing about said axis at such a radial distance therefrom that said comb device sweeps closely around the outer surface of said cylinder, said comb device, in its initial movement, passing over said plate and gathering a sample of fibrous material from the portions protruding through the openings therein, and by a further movement, passing over said card clothing so that the fibers of said sample are straightened out by said clothing into substantially parallel relation.

7. Apparatus for collecting test samples of fibrous material from a loose mass comprising a stationary hollow cylinder composed partly of a plate having a plurality of openings therein and partly of a sheet of card clothing, said openings being relatively large as compared with their distance apart, whereby, when a mass of loose, fibrous material is pressed against the inside of said plate, portions of said material will project slightly through said openings and protrude from the outside of said plate, and a comb device extending parallel with the axis of said cylinder and mounted to swing about said axis at such a radial distance therefrom that said comb device sweeps closely around the outer surface of said cylinder, said comb device, in its initial movement, passing over said plate and gathering a sample of fibrous material from the portions protruding through the openings therein, and by a further movement, passing over said card clothing so that the fibers of said sample are straightened out by said clothing into substantially parallel relation, and means also movable about the axis of said cylinder for cleaning off the excess fibers collected by said card clothing.

8. Apparatus for collecting test samples of fibrous material from a loose mass comprising a stationary hollow cylinder composed partly of a plate having a plurality of openings therein and partly of a sheet of card clothing, said openings being relatively large as compared with their distance apart, whereby, when a mass of loose, fibrous material is pressed against the inside of said plate, portions of said material will project slightly through said openings and protrude from the outside of said plate, and a carriage mounted adjacent said cylinder to swing about the axis thereof, a comb device mounted on said carriage at such a radial distance from said axis that it sweeps closely around the outer surface of said cylinder, said comb device, in its initial movement, passing over said plate and gathering a sample of fibrous material from the portions protruding through the openings therein, and by a further movement, passing over said card clothing so that the fibers of said sample are straightened out by said clothing into substantially parallel relation, and a doifer roll also mounted on said carriage and positioned to engage said card clothing to clean ofi the excess fibers collected by said clothing.

9. Apparatus for collecting test samples of fibrous material from a loose mass comprising a stationary hollow cylinder composed partly of a plate having a plurality of openings therein and partly of a sheet of card clothing, said openings being relatively large as compared with their distance apart, whereby, when a mass of loose, fibrous material is pressed against the inside of said plate, portions of said material Will project slightly through said openings and protrude from the outside of said plate, and a carriage mounted adjacent said cylinder to swing about the axis thereof, a comb device mounted on said carriage at such a radial distance from said axis that it sweeps closely around the outer surface of said cylinder, said comb device, in its initial movement, passing over said plate and gathering a sample of fibrous material from the portions protruding through the openings therein, and by a further movement, passing over said card clothing so that the fibers of said sample are straightened out by said clothing into substantially parallel relation, a doifer roll mounted on said carriage and positioned to engage said card clothing to clean oif the excess fibers collected by said clothing, and a dofling comb also mounted on said carriage and constructed to move into engagement with said doffer roll to remove the fibers therefrom.

10. In apparatus for forming test samples of fibrous material, a sample holder comprising an elongated body having a longitudinal bore open at one side, a core rotatable in said bore, and a series of transversely extending teeth forming a comb secured to said bodyalong one edge ofsaid open bore, said teeth overlying said bore and core. r

11. In apparatus for forming test samples of fibrous material, a sample holder comprising an elongated body having a longitudinal bore open at jone'side, a core rotatable in said bore, said core being substantially cylindrical but having a longitudinal channel formed therein, a series of transversely extending teeth forming a comb secured to said body along one edge of said open bore, and means for rotating said core to bring said channel into a position immediately under the projecting ends of said teeth. I

12. In apparatus for forming test samples of fibrous material, a sample holder comprising an elongated body having a longitudinal bore open at one side, a core rotatable in said bore, said core being generally cylindrical but having thereon a series of circumferential grooves, and a series of transversely extending teeth forming a comb secured to said body, said teeth projecting partially across the open side of said bore and being so positioned as to be received tangentially in said grooves.

13. A sample holder according to claim 12 in which the core is threaded, and the body is a nut working on such threads.

14. In apparatus for forming test samples of fibrous material, a sample holder comprising an elongated body having a longitudinal bore open at one side, a core rotatable in said bore and filling the open side thereof, said core being generally cylindrical but having thereon a series of circumferential grooves, said core being cut away at one side to form a longitudinally extending channel of a depth at least as great as that of said grooves, a series of transversely extending teeth forming a comb secured to said body, said teeth projecting partially across the open side of said bore and spaced apart the same distance as said grooves, and means to rotate said core so as to either cause said grooves to envelop said teeth or cause said channel to underlie said teeth.

15. In apparatus for forming test samples of fibrous material, a sample holder comprising an elongated body having a longitudinal bore open at one side, a core rotatable in said bore and filling the open side thereof, said core being generally cylindrical but having thereon a series of circumferential grooves with ridges between them, said core being cut away at one side to form a longitudinally extending channel, a series of transversely extending teeth secured to said body adjacent the open side of said bore and forming a comb, said teeth being spaced apart the same distance as said grooves, and means to adjust said core to diiferent angles so that either said channel may be brought under said needles to open said comb to permit it to gather fibers, or said grooves may be brought under said needles so that the collected fibers are clamped between the edge of the open side of said bore and the ends of said ridges adjacent said channel, to close said comb.

16. In apparatus of the class described, and in combination, a sample holder comprising a comb device having an open position, permitting it to collect fibers from a mass, and a closed position in which the collected t fibers are locked in position, a fixed hollow cylinder the wall of which comprises a perforated plate, whereby, when a mass of fibrous material is pressed against the inside of said plate, portions of said material will project slightly through the perforations and protrude from the outside of said plate, card clothing carried by a portion of said cylinder wall not occupied by said plate, means for mounting said comb device to swing about the axis of said cylinder at such a radial distance therefrom that it sweeps closely around the outer surface thereof and passes first over said plate and then over said card clothing means carried by said cylinder and co-operating with said comb device and brought into operation during the initial movement of said comb device for assuring that said comb device is in open position as it passes over said plate so that it may collect fibers from the portions of material protruding through the perforations in said plate, and means also carried by said cylinder and co operating with said comb device for automatically shifting said comb device to closed position as it passes over said card clothing.

17. In apparatus for forming test samples of fibrous material, a sample holder comprising an elongated body, a series of transversely extending teeth secured to said body and forming a comb for collecting fibers to be tested, and means rotatably mounted Within said body 15 for locking the collected fibers in position on the comb.

18. In apparatus for forming test samples of fibrous material, a sample holder comprising an elongated body, a series of transversely extending teeth secured to said body and forming a comb for collecting fibers to be tested, and means carried by said body and rotatable with respect thereto for locking the collected fibers in position on the comb.

19. The method of gathering sample fibers from a mass of loose, fibrous material Which comprises pressing the mass against one side of a plate having closely spaced openings therein, so that portions of the materials will project slightly through said openings and protrude from the other side of said plate, and passing a comb over the surface of that side of said plate from which said portions protrude so as to gather fibers from such protruding portions on said comb.

References Cited in the file of this patent UNITED STATES PATENTS 11,534 Sargent Aug. 15, 1854 287,506 Crabb Oct. 30, 1883 1,932,095 Webb Oct. 24, 1933 FOREIGN PATENTS 243,215 Great Britain Nov. 26, 1925 

